Importance of time

Importance of time

Stroke is a medical emergency, and time is critical. Recognising the symptoms of a stroke and being aware of the time factor involved in seeking immediate medical treatment can greatly reduce the chance of permanent damage or disability.

The majority of patients with ischaemic stroke do not reach the hospital soon enough.

Education endeavours should inform the public about symptoms and signs of stroke particularly in the case of high-risk patients and their families and colleagues, and of employees and employers in large companies.

If the first contact is the general practitioner or family doctor, this frequently leads to delays in transportation and the early start of therapy.

Pre-hospital evaluation of potential stroke patients can be accomplished promptly after activation of the emergency medical services (EMS) system.

Urgent evaluation and transport of potential stroke patients is essential.

Time is brain: Act FAST!1-3

Every minute, in which a large vessel ischaemic stroke is untreated, the average patient loses 1.9 million neurons, 13.8 billion synapses, and 12 km of axonal fibres.

Each hour in which treatment fails to occur, the brain loses as many neurons as it does in almost 3.6 years of normal aging.

The penumbra area (see Pathophysiology section) represents potentially salvageable brain tissue if perfusion of the tissue can be restored in time (before the tissue becomes completely ischaemic and dies).

NINDS recommends a door-to-needle time (DTN) of 1 hour or less.

Streamlining of local guidelines and standard operating procedures may shorten the DTN in experienced stroke centres to <30 min on average.

However, only approximately 11% of all stroke patients who are thrombolysed receive rt-PA within 90 minutes of symptom onset.

rt-PA effects are time dependent4-9

The 2010 pooled analysis of rt-PA trials for ischaemic stroke showed that the earlier treatment is initiated, the better the outcome, and the lower the number of patients needed to treat (NNT) with rt-PA to achieve one additional favourable outcome (classified as a modified Rankin score of 0-1) (Figure 1):

Figure 1: NNT to reach a modified Rankin score of 0-1 according to the time from onset of stroke to the start of treatment4

Treatment within 0-90 min → NNT 4-5

Treatment within 90-180 min → NNT 9

Treatment within 3-4.5 hours → NNT 14

The SITS-MOST registry shows that:

"Real-life" treatment with rt-PA within 3 hours of symptom onset results in greater independence in activities of daily living when compared with treatment given during randomised controlled trials (RCTs) (54.8% vs. 50.1%; SITS-MOST vs. RCTs, respectively).

SITS-ISTR confirms the safety and efficacy of rt-PA for the thrombolysis of ischaemic stroke within the approved 3-hour time window as well as in the 3-4.5 hour time window.

rt-PA is not licensed for use beyond 4.5 hours after stroke symptom onset.*

All patients being considered for rt-PA therapy must undergo urgent brain imaging (CT or MRI), a physical examination, blood tests, a neurological assessment, and a patient history - all within a timeframe that will allow rt-PA treatment to begin within 4.5 hours* of symptom onset.

The concept that if a patient arrives early, the doctor has more time, is totally inacceptable, as studies show that the earlier treatment is implemented, the better the outcome.

*As this differs in some countries, please check your local prescribing regulations for the currently recommended time window for the use of rt-PA.